foreach () { my ($w1, $w2) = split / /, $_; my %common = (); foreach ( split //, $w1){ eval "\$foo=\$w2=~tr/$_/$_/" unless exists $common{$_}; $common {$_}=1 if $foo; } print "$w1 and $w2 have ", join (", ",sort keys %common)," in common\n"; } __DATA__ perl monk help temp frood hoopysdf bilbo baggins jibber jabber